A device has been proposed that simultaneously cuts a columnar workpiece into sheet wafers by using a plurality of parallel cutting wire sections. One cutting method is a wire saw method in which a wafer is machined from a workpiece by using an abrasive action that involves pressing an abrasive material that is in between the cutting wire section and the workpiece against the surface of the workpiece or pressing a wire that has a surface to which is adhered hard microabrasive grains, e.g., diamond, against the surface of the workpiece. Besides the wire saw method, a method has been proposed called a wire electrical discharge machining method in which a machining power source is fed to each cutting wire section in order to generate electrical discharge between the cutting wire sections and the workpiece and the workpiece is thus removed by using the electrical discharge energy.
In order to increase productivity, a wafer machining apparatus employing each of the two types of machining methods described above includes a cutting wire section formed by repeatedly winding a single wire across a plurality of guide rollers to create a plurality of wires arranged in parallel with one another at regular intervals; therefore, the workpiece can be cut simultaneously at a plurality of sites.